System and method for detecting laser irradiated embedded material in a structure

ABSTRACT

A detection system is used during irradiation of an interaction region of a structure with laser light. The structure includes embedded material. The detection system includes means for receiving light emitted from the interaction region. The detection system further includes means for separating the received light into a spectrum of wavelengths. The detection system further includes means for analyzing at least a portion of the spectrum for indications of embedded material within the interaction region.

CLAIM OF PRIORITY

This application is a continuation of U.S. patent application Ser. No.10/691,444 filed Oct. 22, 2003 now U.S. Pat. No. 7,286,223, which isincorporated in its entirety by reference herein, and which claimsbenefit under 35 U.S.C. §119(e) to U.S. Provisional Patent ApplicationNo. 60/456,043, filed Mar. 18, 2003, to U.S. Provisional PatentApplication No. 60/471,057, filed May 16, 2003, and to U.S. ProvisionalPatent Application No. 60/496,460, filed Aug. 20, 2003, each of which isincorporated in its entirety by reference herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was funded, in part, by the Federal Emergency ManagementAgency as part of the Robert T. Stafford Disaster Relief and EmergencyAssistance Act (42 U.S.C. §5121 et seq.).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of material processing,particularly, to an apparatus and method for drilling, cutting, andsurface processing of materials using energy waves.

2. Description of the Related Art

Those in the wide ranging materials processing industries have longrecognized the need for non-disruptive material processing. In the past,virtually all material processing, including drilling, cutting,scabbling, and the like have included numerous disruptive aspects (e.g.,noise, vibration, dust, vapors, and fumes). Material processinggenerally includes mechanical technologies such as drilling, hammering,and other power assisted methods, and water jet based technologies.Demonstrative of the problems of material processing, U.S. Pat. No.5,085,026 is highly illustrative. The '026 device requires mechanicaldrilling of materials such as concrete or other masonry, and generatesall the disruptive aspects noted above.

SUMMARY OF THE INVENTION

In certain embodiments, a detection system is used during irradiation ofan interaction region of a structure with laser light. The structurecomprises embedded material. The detection system comprises a focusinglens positioned to receive light emitted from the interaction region.The detection system further comprises an optical fiber opticallycoupled to the focusing lens to receive light from the focusing lens.The detection system further comprises a spectrometer optically coupledto the optical fiber to receive light from the optical fiber. Thespectrometer is adapted for analysis of the light for indications of theembedded material within the interaction region.

In certain embodiments, a detection system is used during irradiation ofan interaction region of a structure with laser light. The structurecomprises embedded material. The detection system comprises means forfocusing light emitted from the interaction region. The detection systemfurther comprises means for separating the focussed light into aspectrum of wavelengths. The detection system, further comprises meansfor analyzing at least a portion of the spectrum for indications ofembedded material within the interaction region.

In certain embodiments, a method detects rebar within a laser-irradiatedinteraction region of a structure comprising embedded material. Themethod comprises focussing light from the interaction region. The methodfurther comprises separating the light into a spectrum of wavelengths.The method further comprises analyzing at least a portion of thespectrum for indications of embedded material within the interactionregion.

For purposes of summarizing the present invention, certain aspects,advantages and novel features of the present invention have beendescribed herein above. It is to be understood, however, that notnecessarily all such advantages may be achieved in accordance with anyparticular embodiment of the present invention. Thus, the presentinvention may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

Without limiting the scope of the present invention as claimed below andreferring now to the drawings and figures:

FIG. 1 schematically illustrates an embodiment of an apparatus forprocessing a surface of a structure;

FIG. 2 schematically illustrates a laser base unit compatible withembodiments described herein;

FIG. 3A schematically illustrates a laser head in accordance withembodiments described herein;

FIGS. 3B and 3C schematically illustrate two alternative embodiments ofthe laser head;

FIG. 4 schematically illustrates a cross-sectional view of a containmentplenum in accordance with embodiments described herein;

FIG. 5 schematically illustrates a laser head comprising a sensoradapted to measure the relative distance between the laser head and theinteraction region;

FIGS. 6A and 6B schematically illustrate two opposite elevatedperspectives of an embodiment in which the laser manipulation systemcomprises an anchoring mechanism adapted to be releasably coupled to thestructure and a positioning mechanism coupled to the anchoring mechanismand coupled to the laser head;

FIG. 7 schematically illustrates an embodiment of an attachmentinterface of the anchoring mechanism;

FIG. 8 schematically illustrates an exploded view of one embodiment ofthe positioning mechanism along with the attachment interfaces of theanchoring mechanism;

FIG. 9 schematically illustrates an embodiment of a first-axis positionsystem;

FIG. 10 schematically illustrates an embodiment of a second-axisposition system;

FIGS. 11A and 11B schematically illustrate an embodiment of an interfacein two alternative configurations;

FIG. 12 schematically illustrates an embodiment of a laser headreceiver;

FIG. 13 schematically illustrates an embodiment of a support structurecoupled to the other components of the apparatus;

FIG. 14A schematically illustrates an embodiment of a suspension-basedsupport system coupled to the apparatus;

FIG. 14B schematically illustrates an embodiment of the apparatuscomprising suspension-based support connectors;

FIG. 15 schematically illustrates an embodiment of a controllercomprising a control panel, a microprocessor, a laser generatorinterface, a positioning system interface, a sensor interface, and auser interface;

FIG. 16 schematically illustrates a control pendant comprising a screenand a plurality of buttons;

FIG. 17A illustrates an exemplary “MAIN SCREEN” display of the controlpendant;

FIG. 17B illustrates an exemplary “SELECT OPERATION SCREEN” display ofthe control pendant;

FIG. 17C illustrates an exemplary “CIRCLE SETUP/OPERATION SCREEN”display of the control pendant;

FIG. 17D illustrates an exemplary “PIERCE SETUP/OPERATION SCREEN”display of the control pendant;

FIG. 17E illustrates an exemplary “CUT SETUP/OPERATION SCREEN” displayof the control pendant;

FIG. 17F illustrates an exemplary “SURFACE KEYING SETUP/OPERATIONSCREEN” display of the control pendant;

FIG. 17G illustrates an exemplary “FAULT SCREEN” display of the controlpendant;

FIG. 17H illustrates an exemplary “MAINTENANCE SCREEN” display of thecontrol pendant;

FIG. 18 schematically illustrates a detector compatible with embodimentsdescribed herein; and

FIG. 19 shows a graph of the light spectrum of wavelengths detected uponirradiating concrete with laser light and the light spectrum detectedupon irradiating concrete with embedded rebar.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reducing the disruptive aspects of material processing has long been agoal of those in materials processing industries, particularly inindustries that require materials processing within or near occupiedstructures, such as is common in renovation and many other applications.Such long-felt needs have been particularly prevalent in seismicallyactive areas of the earth, where there is a pressing need for aneffective and economical means of retrofitting occupied structures toincrease the safety of these structures.

Prior technologies are plagued by disruptive characteristics, therebymaking them virtually unsuitable for retrofitting occupied structures.Additionally, such material processing technologies often presentdangerous and costly “cut through” dangers.

“Cut through” dangers include instances such as a worker unintentionallycutting an embedded object while drilling through the subject material.For example, a construction worker drilling a hole in an existingconcrete wall may accidentally encounter reinforcing steel or rebar, orembedded utilities, such as live electrical conduit and conductors. Suchan incident may result in costly damage to tools or the subjectmaterial, as well as potentially deadly consequences (e.g.,electrocution) for workers. Traditional drilling methods also caninclude “punch through” dangers of unexpectedly punching through thematerial drilled and damaging structures or personnel on the oppositeside of the material.

In addition, traditional material processing equipment has beenextremely burdensome to operate. Handheld power drilling and hammeringdevices commonly weigh in excess of fifty pounds and are often requiredto be held overhead by the operator for extended period of time.Conventional devices also typically produce jarring forces that theoperator must absorb while holding the device. Besides the potentiallyinjurious jarring forces, sustained heavy lifting, and “cut through”dangers, the operator and those in the vicinity of the device may beexposed to falling or projectile debris, as well as dust, fumes, vapors,vibration, and noise. This level of noisome activity is unsuitable ingeneral for occupied structures, and is entirely unsuitable forstructures used as hospitals, laboratories, and the like, where noiseand vibration can be completely unacceptable.

What continues to be needed but missing from this field of art is anon-disruptive material processing technology that overcomes thedrawbacks illustrated above. In certain embodiments described herein,energy waves are directed toward the surface to be processed to overcomesome or all of such drawbacks. The energy waves of certain embodimentsare electromagnetic waves (e.g., laser light, microwaves), while inother embodiments, they are acoustic waves (e.g., ultrasonic waves).However, in certain embodiments, such cutting units can be as bulky andoften are as difficult to maneuver as their mechanical counterparts. Inaddition, lasers can be subject to the same “cut through” dangers asdescribed above, wherein objects hidden within the matrix of thematerial to be processed can be inadvertently damaged. Lasers can alsopose additional dangers of “punch through” with danger to persons orobjects in the path of the laser beam. Lasers can also presentcomplexities in removing drilled material from a cut or a drilled hole.In certain embodiments, the laser system would incorporate a remotelaser generator communicating with a portable processing head thatincorporates numerous non-disruptive and safety features allowing thesystem to be utilized within or near occupied structures.

Certain embodiments of the present invention provide fast materialprocessing while addressing many of the shortcomings of priortechnologies and allowing for heretofore unavailable benefits (e.g.,reduced disruption to activities within the structure). In certainembodiments, the method and apparatus utilize fiber connections betweenelements such that noisy, bulky, and heavy elements can operate at asignificant distance from the actual work area. Certain embodiments arelow in both noise and vibration during operation, and effectively removedust and debris. Certain embodiments include a detection system toreduce the dangers of “cut through” or “punch through.” Certainembodiments enhance worker safety by allowing workers to be located awayfrom the work area during material processing. Certain embodiments areseparable into man-portable pieces (e.g., less than 50 pounds) tofacilitate transportation to locations in proximity to or within thestructure being processed by providing easy and fast portability andset-up.

Certain embodiments of the present invention provide a method andapparatus for processing fragile structures which may be damaged byconventional processing techniques. For example, using conventional sawsfor processing concrete grain silos as part of a retrofit orrefurbishment process may result in vibrations damaging to otherportions of the silo. Using a laser to process the fragile structure canreduce the collateral damage done to the structure during processing.Furthermore, certain embodiments described herein are easilyassembled/disassembled, so they can be used in otherwise inaccessibleportions of the structures. While embodiments described herein aredisclosed in terms of processing man-made structures, in still otherembodiments, the present invention can be useful for processing naturalformations (e.g., as part of a mining or drilling operation).

The method and apparatus described herein represent a significantadvance in the state of the art. Various embodiments of the apparatuscomprise new and novel arrangements of elements and methods that areconfigured in unique and novel ways and which demonstrate previouslyunavailable but desirable capabilities. In particular, certainembodiments of the present invention provide a material processingmethod that is quiet, substantially vibration-free, and less likely toexude dust, debris, or noxious fumes. Additionally, certain embodimentsallow a higher rate of material processing than do conventionaltechnologies.

The detailed description set forth below in connection with the drawingsis intended merely as a description of various embodiments of thepresent invention, and is not intended to represent the only form inwhich the present invention may be constructed or utilized. Thedescription sets forth illustrated embodiments of the designs,functions, apparatus, and methods of implementing the invention. It isto be understood, however, that the same or equivalent functions andfeatures may be accomplished by different embodiments that are alsointended to be encompassed within the spirit and scope of the invention.

FIG. 1 schematically illustrates an embodiment of an apparatus 50 forprocessing a structure having a surface. The apparatus 50 comprises alaser base unit 300, a laser manipulation system 100, and a controller500. The laser base unit 300 is adapted to provide laser light to aninteraction region and includes a laser generator 310 and a laser head200 coupled to the laser generator 310. The laser head 200 is adapted toremove the material from the interaction region. The laser manipulationsystem 100 includes an anchoring mechanism 110 adapted to be releasablycoupled to the structure and a positioning mechanism 121 coupled to theanchoring mechanism 110 and coupled to the laser head 200. The lasermanipulation system 100 is adapted to controllably adjust the positionof the laser head 200 relative to the structure. The controller 500 iselectrically coupled to the laser base unit 300 and the lasermanipulation system 100. The controller 500 is adapted to transmitcontrol signals to the laser base unit 300 and to the laser manipulationsystem 100 in response to user input.

In certain embodiments, the laser head 200 is releasably coupled to thelaser generator 310 and is releasably coupled to the positioningmechanism 121. In certain embodiments, the positioning mechanism 121 isreleasably coupled to the anchoring mechanism 110, and the controller500 is releasably coupled to the laser base unit 300 and the lasermanipulation system 100. Such embodiments can provide an apparatus 50which can be reversibly assembled and disassembled to facilitatetransportation of the apparatus 50 to locations in proximity to orwithin the structure being processed.

Laser Base Unit

Certain embodiments of the laser base unit 300 are described below.While the laser base unit 300 is described below as comprising separatecomponents, other embodiments can include combinations of two or more ofthese components in an integral unit.

Laser Generator

FIG. 2 schematically illustrates a laser base unit 300 compatible withembodiments described herein. In certain embodiments, the laser baseunit 300 comprises a laser generator 310 and a cooling subsystem 320.The laser generator 310 is coupled to a power source (not shown) whichprovides electrical power of appropriate voltage, phase, and amperagesufficient to power the laser generator 310. The power source can alsobe portable in certain embodiments, and can operate without coolingwater, air, or power from the facility at which the apparatus 50 isoperating. Exemplary power sources include, but are not limited to,diesel-powered electric generators.

In certain embodiments, the laser generator 310 preferably comprises anarc-lamp-pumped Nd:YAG laser, but may alternatively comprise a CO₂laser, a diode laser, a diode-pumped Nd:YAG laser, a fiber laser, orother types of laser systems. The laser generator 310 can be operated ineither a pulsed mode or a continuous-wave mode. One exemplary lasergenerator 310 in accordance with embodiments described herein includes aTrumpf 4006D, 4000-watt, continuous-wave laser available from TrumpfLasertechnik GmbH of Ditzingen, Germany. In other exemplary embodiments,a Yb-doped fiber laser or an Er-doped fiber laser can be used. Othertypes of lasers are compatible with embodiments of the presentinvention. Depending on the requirements unique to a given applicationof the method and apparatus described herein, one skilled in the artwill be able to select the optimal laser for the purposes at hand.

In certain embodiments, the laser generator 310 can be located within ashipping container for ease of transport and storage. The lasergenerator 310 generates laser light which is preferably deliveredthrough a glass fiber-optic cable from the laser generator 310 to thework location.

In certain alternative embodiments, the laser generator 310 comprises agas-based CO₂ laser which generates laser light by the excitation of CO₂gas. Such lasers provide high power output (e.g., ˜100 W-50 kW) at highefficiencies (e.g., ˜5-13%), and are relatively inexpensive. The laserlight generated by such gas-based CO₂ lasers is typically delivered bymirrors and by using a system of ducts or arms to deliver the laserlight around bends or corners.

In certain alternative embodiments, the laser generator 310 comprises adiode laser. Such diode lasers are compact compared to gas and Nd:YAGlasers so they can be used in a direct delivery configuration (e.g., inclose proximity to the work site). Diode lasers provide high power(e.g., ˜10 W-6 kW) at high power efficiencies (e.g., ˜25-40%). Incertain embodiments, the laser light from a diode laser can be deliveredvia optical fiber, but with some corresponding losses of power.

Embodiments using a Nd:YAG laser can have certain advantages overembodiments with CO₂ lasers or diode lasers. There is long industrialexperience with Nd:YAG lasers in the materials processing industry andthey provide high power (e.g., ˜100 W-6 kW). Additionally, the laserlight from a Nd:YAG laser can be delivered by optical fiber with onlyslight power losses (e.g., ˜12%) through a relatively small and longoptical fiber. This permits the staging of the laser generator 310 andsupport equipment in locations relatively far (e.g., about 100 meters)from the work area. Maintaining the laser generator 310 at a distancefrom the surface being processed allows the remainder of the apparatus50 to be smaller and more portable.

Arc-lamp-pumped Nd:YAG lasers use an arc lamp to excite a Nd:YAG crystalto generate laser light. Diode-pumped Nd:YAG lasers use diode lasers toexcite the Nd:YAG crystal, resulting in an increase in power efficiency(e.g., ˜10-25%, as compared to less than 5% for arc-lamp-pumped Nd:YAGlasers). This increased efficiency results in the diode-pumped laserhaving a better beam quality, and requiring a smaller cooling subsystem320. An exemplary arc-lamp-pumped Nd:YAG laser is available from TrumpfLasertechnik GmbH of Ditzingen, Germany.

Typically, the generation of laser light by the laser generator 310creates excess heat which is preferably removed from the laser generator310 by the cooling subsystem 320 coupled to the laser generator 310. Theamount of cooling needed is determined by the size and type of laserused, but can be about 190 kW of cooling capacity. The cooling subsystem320 can utilize excess cooling capability at a job site, such as anexisting process water or chilled water cooling subsystem.Alternatively, a unitary cooling subsystem 320 dedicated to the lasergenerator 310 is preferably used. Unitary cooling subsystems 320 may beair- or liquid-cooled.

In certain embodiments, as schematically illustrated in FIG. 2, thecooling subsystem 320 comprises a heat exchanger 322 and a water chiller324 coupled to the laser 310 to provide sufficient circulatory coolingwater to the laser generator 310 to remove the excess heat. The heatexchanger 322 preferably removes a portion of the excess heat from thewater, and circulates the water back to the water chiller 324. The waterchiller 324 cools the water to a predetermined temperature and returnsthe cooling water to the laser generator 310. Exemplary heat exchangers322 and water coolers 324 in accordance with embodiments describedherein are available from Trumpf Lasertechnik GmbH of Ditzingen,Germany.

Laser Head

In certain embodiments, the laser head 200 is coupled to the lasergenerator 310 and serves as the interface between the apparatus 50 andthe structure being irradiated. As schematically illustrated by FIG. 1,an energy conduit 400 couples the laser head 200 and the laser generator310 and facilitates the transmission of energy from the laser generator310 to the laser head 200. In certain embodiments, the energy conduit400 comprises an optical fiber which transmits laser light from thelaser generator 310 to the laser head 200. In other embodiments, theenergy conduit 400 comprises conductors that may include fiber-optic,power, or control wiring cables.

FIG. 3A schematically illustrates a laser head 200 in accordance withembodiments described herein. The laser head 200 comprises a connector210, at least one optical element 220, a housing 230, and a containmentplenum 240. In certain embodiments, the connector 210 is coupled to thehousing 230, is optically coupled to the laser generator 310 via theenergy conduit 400, and is adapted to transmit laser light from thelaser generator 310. The optical element 220 can be located within theconnector 210, the housing 230, or the containment plenum 240. FIG. 3Aillustrates an embodiment in which the optical element 220 is within thehousing 230. In embodiments in which the conduit 400 provides laserlight to the laser head 200, the laser light is transmitted through theoptical element 220 prior to impinging on the structure beingirradiated.

FIG. 3B schematically illustrates one configuration of a laser head 200in accordance with embodiments described herein. The housing 230comprises a distal portion 232, an angle portion 234, and a proximalportion 236. As used herein, the terms “distal” and “proximal” havetheir standard definitions, referring generally to the position of theportion relative to the interaction region. The connector 210 is coupledto the distal portion 232, which is coupled to the angle portion 234,which is coupled to the proximal portion 236, which is coupled to thecontainment plenum 240. Configurations such as that illustrated by FIG.3B can be used for drilling and scabbling the surface of the structure(e.g., concrete wall). Various components of the laser head 200 areavailable from Laser Mechanisms, Inc. of Farmington Hills, Mich.

In certain embodiments in which the energy conduit 400 comprises anoptical fiber, the connector 210 receives laser light transmitted fromthe laser generator 310 through the optical fiber to the laser head 200.In certain such embodiments, the connector 210 comprises a lens 212which collimates the diverging laser light emitted by the conduit 400.The lens 212 can comprise various materials which are transmissive andwill refract the laser light in a desired amount. Such materialsinclude, but are not limited to, borosilicate crown glass (BK7), quartz(SiO₂), zinc selenide (ZnSe), and sodium chloride (NaCl). The materialof the lens 212 can be selected based on the quality, cost, andstability of the material. Borosilicate crown glass is commonly used fortransmissive optics with Nd:YAG lasers, and zinc selenide is commonlyused for transmissive optics with CO₂ lasers.

The lens 212 can be mounted in a removable assembly in certainembodiments to facilitate cleaning, maintenance, and replacement of thelens 212. In addition, the mounting of the lens 212 can be adjustable(e.g., using thumbscrews or Allen hex screws) so as to optimize thealignment and focus of the light beam. In certain embodiments, the lens212 can provide additional modification of the beam profile (e.g.,focussing, beam shape).

The collimated laser light of certain embodiments is then transmittedthrough the laser head 200 via other optical elements within the laserhead 200. In certain embodiments, the distal portion 232 comprises agenerally straight first tube through which laser light propagates tothe angle portion 234, and the proximal portion 236 comprises agenerally straight second tube through which the laser light from theangle portion 234 propagates. In certain embodiments, the distal portion232 contains a lens 233, and the angle portion 234 contains a mirror 235which directs the light through the proximal portion 236 and thecontainment plenum 240 onto the structure. In other embodiments, otherdevices (e.g., a prism) can be used in the angle portion 234 to directthe light through the proximal portion 236 and the containment plenum240 onto the structure.

The lens 233 can be mounted in a removable assembly in certainembodiments to facilitate cleaning, maintenance, and replacement of thelens 233. In addition, the mounting of the lens 233 can be adjustable(e.g., using thumbscrews or Allen hex screws) so as to optimize thealignment and focus of the light beam. In certain embodiments, the lens233 focuses the light received from the lens 212, while in otherembodiments, the lens 233 can provide additional modification of thebeam profile (e.g., beam shape). Exemplary lenses 233 include, but arenot limited to, a 600-mm focal length silica plano-convex lens (e.g.,Part No. PLCX-50.8-309.1-UV-1064 available from CVI Laser Corp. ofAlbuquerque, N. Mex.). The lens 233 can comprise various materials whichare transmissive and will refract the laser light in a desired amount.Such materials include, but are not limited to, borosilicate crownglass, quartz, zinc selenide, and sodium chloride. Exemplary lensmounting assemblies include, but are not limited to, Part Nos. PLALH0097and PLFLH0119 available from Laser Mechanisms, Inc. of Farmington Hills,Mich.

In the embodiment schematically illustrated by FIG. 3B in which thedistal portion 232 is substantially perpendicular to the proximalportion 236, the mirror 235 reflects the light through an angle ofapproximately 90 degrees. Other embodiments are configured to reflectthe light through other angles. The mirror 235 can be mounted on aremovable assembly in certain embodiments to facilitate cleaning,maintenance, and replacement of the mirror 235. In addition, themounting of the mirror 235 can be adjustable (e.g., using thumbscrews orAllen hex screws) so as to optimize the alignment and focus of the lightbeam. In certain embodiments, the mirror 235 can also have a curvatureor otherwise be configured so as to focus the light beam or otherwisemodify the beam profile (e.g., beam shape). Exemplary mirrors 235include, but are not limited to, metal mirrors such as copper mirrors(e.g., Part Nos. PLTRG19 and PLTRC0024 from Laser Mechanisms, Inc. ofFarmington Hills, Mich.), and gold-coated copper mirrors (e.g., Part No.PLTRC0100 from Laser Mechanisms, Inc.). In other embodiments,dielectric-coated mirrors can be used.

FIG. 3C schematically illustrates another configuration of a laser head200 in accordance with embodiments described herein. The housing 230comprises the distal portion 232, a first angle portion 234, a secondangle portion 234′, and the proximal portion 236. The connector 210 iscoupled to the distal portion 232, which is coupled to the first angleportion 234, which is coupled to the second angle portion 234′, which iscoupled to the proximal portion 236, which is coupled to the containmentplenum 240. Configurations such as that illustrated by FIG. 3C can beused for cutting the structure in spatially constrained regions (e.g.,cutting off portions of a concrete wall near a corner or protrusion).

As described above, in certain embodiments, the connector 210 comprisesa lens 212 and the distal portion 232 is tubular and contains a lens233. The first angle portion 234 of the embodiment illustrated by FIG.3C contains a first mirror 235 which directs the light to the secondangle portion 234′ which contains a second mirror 235′. The secondmirror 235′ directs the light through the proximal portion 236, whichcan be tubular, and through the containment plenum 240 onto thestructure.

In the embodiment schematically illustrated by FIG. 3C, the first mirror235 reflects the light through an angle of approximately 90 degrees andthe second mirror 235′ reflects the light through an angle ofapproximately −90 degrees such that the proximal portion 236 issubstantially parallel to the distal portion 232. In such embodiments,the light emitted by the containment plenum 240 is substantiallyparallel to, but displaced from, the light propagating through thedistal portion 232. Other embodiments have the first mirror 235 and thesecond mirror 235′ configured to reflect the light through other angles.Certain embodiments comprise a straight tubular portion between thefirst angle portion 234 and the second angle portion 234′ to provideadditional displacement of the light emitted by the containment plenum240 from the light propagating through the distal portion 232.

In certain embodiments, the coupling between the distal portion 232 andthe first angle portion 234 is rotatable. In certain other embodiments,the coupling between the first angle portion 234 and the second angleportion 234′ is rotatable. These rotatable couplings can comprise swiveljoints which can be locked in position by thumbscrews. Such embodimentsprovide additional flexibility in directing the light emitted by thecontainment plenum 240 in a selected direction. In certain embodiments,the selected direction is non-planar with the light propagating throughthe distal portion 232.

As described above, one or both of the first mirror 235 and the secondmirror 235′ can be mounted on a removable assembly in certainembodiments to facilitate cleaning, maintenance, and replacement. Inaddition, the mountings of the first mirror 235 and/or the second mirror235′ can be adjustable (e.g., using thumbscrews or Allen hex screws) soas to optimize the alignment and focus of the light beam. In certainembodiments, one or both of the first mirror 235 and the second mirror235′ can also have a curvature or otherwise be configured so as to focusthe light beam or otherwise modify the beam profile (e.g., beam shape).

In certain embodiments, one or more of the optical elements 220 withinthe laser head 200 (e.g., lens 212, lens 233, mirror 235, mirror 235′)are water-cooled or air-cooled. Cooling water can be supplied by a heatexchanger located near the laser head 200 and dedicated to providingsufficient water flow to the laser head 200. In certain suchembodiments, the conduits for the cooling water for each of the opticalelements 220 can be connected in series so that the cooling water flowssequentially in proximity to the optical elements 220. In otherembodiments, the conduits are connected in parallel so that separateportions of the cooling water flow in proximity to the various opticalelements 220. Exemplary heat exchangers include, but are not limited toa Miller Coolmate™ 4, available from Miller Electric Manufacturing Co.of Appleton, Wis. The flow rate of the cooling water is preferably atleast approximately 0.5 gallons per minute.

In certain embodiments, the laser head 200 comprises a containmentplenum 240 coupled to the proximal portion 236 and which interfaces withthe structure. In certain embodiments, the containment plenum 240 isadapted to confine material (e.g., debris and fumes generated duringlaser processing) removed from the structure and remove the materialfrom the interaction region. The containment plenum 240 can also befurther adapted to reduce noise and light emitted from the interactionregion out of the containment plenum 240 (e.g., into the nominal hazardzone (“NHZ”) of the laser). One goal of the containment plenum 240 canbe to ensure that no laser radiation in excess of the accessibleemission limit (“AEL”) or maximum-permissible exposure (“MPE”) limitreaches the eye or skin of any personnel.

FIG. 4 schematically illustrates a cross-sectional view of a containmentplenum 240 in accordance with embodiments described herein. Thecontainment plenum 240 of FIG. 4 comprises a plenum housing 242, awindow 243, a nozzle 244, a resilient interface 246, an extraction port248, and a compressed gas inlet 249. The plenum housing 242 can becoupled to a source of laser light (e.g., the proximal portion 236 ofthe laser head 200) and can provide structural support for the othercomponents of the containment plenum 240. Exemplary materials for theplenum housing 242 include, but are not limited to, metals (e.g.,aluminum, steel) which can be in the form of thin flexible sheets,ceramic materials, glass or graphite fibers, and fabric made from glassor graphite fibers. In certain embodiments, the plenum housing 242 iseither air-cooled or water-cooled to reduce heating of the plenumhousing 242. Coolant conduits for the plenum housing 242 can be coupledin series or in parallel with the coolant conduits for other componentsof the laser head 200.

The window 243 can be positioned upstream of the nozzle 244 and withinthe propagation path of the laser light from the proximal portion 236 tothe structure. As used herein, the terms “downstream” and “upstream”have their ordinary meanings referring to the propagation direction ofthe laser light and to the direction opposite to the propagationdirection of the laser light, respectively. In such embodiments, thelight propagating through the containment plenum 240 reaches the window243 prior to reaching the nozzle 244. In such embodiments in which thelight propagates downstream through the window 243, the window 243 issubstantially transparent to the laser light. The window 243 can bemounted within the plenum housing 242 to transmit the laser light in thedownstream direction. Exemplary windows 243 include, but are not limitedto, a silica window (e.g., Part No. W2-PW-2037-UV-1064-0 available fromCVI Laser Corp. of Albuquerque, N. Mex.).

Dust and/or dirt on the optical elements of the laser head 200 canabsorb an appreciable fraction of the laser light, resulting innonuniform heating which can damage the optical elements. In certainembodiments, the window 243 is mounted within the plenum housing 242 toprovide a barrier to the upstream transport of dust, smoke, or otherparticulate matter generated by the interaction of the laser light andthe structure. In this way, the window 243 can facilitate protection ofthe upstream optical elements within the other portions of the laserhead 200.

The window 243 can be mounted in a removable assembly in certainembodiments to facilitate cleaning, maintenance, and replacement of thewindow 243. In certain embodiments, the window 243 focuses the lightreceived from the proximal portion 236, while in other embodiments, thewindow 243 can provide additional modification of the beam profile(e.g., beam shape). In such embodiments, the mounting of the window 243can be adjustable (e.g., using thumbscrews or Allen hex screws) so as tooptimize the alignment and focus of the light beam. Exemplary windowmounting assemblies include, but are not limited to, Part Nos. PLALH0097and PLFLH0119 available from Laser Mechanisms, Inc. of Farmington Hills,Mich. In certain embodiments, the window 243 is either air-cooled orwater-cooled.

The laser light transmitted through the window 243 is emitted throughthe nozzle 244 towards the interaction region of the structure. Thelaser light can be focussed near the opening of the nozzle 244.Exemplary materials for the nozzle 244 include, but are not limited tometals (e.g., copper). In certain embodiments, the nozzle 244 is eitherair-cooled or water-cooled to reduce heating of the nozzle 244. Coolantconduits for the nozzle 244 can be coupled in series or in parallel withthe coolant conduits for other components of the laser head 200.

The laser light propagating through the nozzle 244 preferably does notimpinge the nozzle 244 (termed “clipping”) to avoid excessively heatingand damaging the nozzle 244. Improper alignment of the laser lightthrough the laser head 200 can cause clipping. The opening of the nozzle244 can be sufficiently large so that the laser light does notappreciably interact with the nozzle 244. In certain embodiments, thenozzle 244 is approximately 0.3 inches in diameter.

In certain embodiments, the resilient interface 246 of the containmentplenum 240 is adapted to contact the structure and to substantiallysurround the interaction region, thereby facilitating confinement andremoval of material from the interaction region. In addition, theresilient interface 246 can facilitate blocking light and/or sound fromescaping outside the containment plenum 240. Exemplary resilientinterfaces 246 include, but are not limited to, a wire brush.

In certain embodiments, the extraction port 248 of the containmentplenum 240 is adapted to extract an appreciable portion of the material(e.g., gas, vapor, dust, and debris) generated within the interactionregion during operation. The extraction port 248 can be coupled to avacuum generator (not shown) which creates a vacuum to pull material(e.g., airborne particulates, gases, and vapors) from the interactionregion. In this way, the extraction port 248 can provide a pathway forremoval of the material from the containment plenum 240.

In certain embodiments, the compressed gas inlet 249 is adapted toprovide compressed gas (e.g., air) to the containment plenum 240. Incertain embodiments, the compressed gas inlet 249 is fluidly coupled tothe nozzle 244 which is adapted to direct a compressed gas stream to theinteraction region. In certain embodiments, compressed gas flowscoaxially with the laser light through the nozzle 244. The window 243 ofcertain embodiments provides a surface against which the compressed gasexerts pressure. In this way, the compressed gas can flow through thenozzle 244 to the interaction region at a selected pressure andvelocity.

The compressed gas flowing from the compressed gas inlet 249 through thenozzle 244 can be used to deter dust, debris, smoke, and otherparticulate matter from entering the nozzle 244. In this way, thecompressed gas can facilitate protection of the window 243 from suchparticulate matter. In addition, the compressed gas can be directed bythe nozzle 244 to the interaction region so as to facilitate removal ofmaterial from the interaction region. The nozzle 244 can be used in thismanner in embodiments in which the structure includes concrete with ahigh percentage of Si, so that the resultant glassy slag is sufficientlyviscous and more difficult to remove from the interaction region.

In certain embodiments, the compressed air is substantially free of oil,moisture, or other contaminants to avoid contaminating the surface ofthe window 243 and potentially damaging the window 243 by nonuniformheating. An exemplary source of instrument quality (“IQ”) compressed airis the 300-IQ air compressor available from Ingersoll-Rand Air SolutionsGroup of Davidson, N.C. The source of compressed air preferably providesair at a sufficient flow rate determined in part by the length of thehose delivering the air, and the number of components using the air andtheir requirements.

In certain embodiments, the air compressor can be located hundreds offeet away from the laser head 200. In such embodiments, the source ofcompressed air can comprise an air dryer to reduce the amount ofmoisture condensing in the air conduits or hoses between the aircompressor and the laser head 200. An exemplary air dryer in accordancewith embodiments described herein is the 400 HSB air dryer availablefrom Zeks Compressed Air Solutions of West Chester, Pa.

In certain embodiments, as schematically illustrated in FIG. 5, thelaser head 200 comprises a sensor 250 adapted to measure the relativedistance between the laser head 200 and the interaction region. FIG. 5schematically illustrates an embodiment in which the containment plenum240 comprises the sensor 250, although other locations of the sensor 250are also compatible with embodiments described herein. As material isremoved from the structure, the interaction region extends into thestructure. The sensor 250 then provides a measure of the depth of theinteraction region from the surface of the structure. The sensor 250 canuse various technologies to determine this distance, including, but notlimited to, acoustic sensors, infrared sensors, tactile sensors, andimaging sensors. In certain embodiments in which laser scabbling ormachining is performed, a sensor 250 comprising a diode laser andutilizing triangulation could be used to determine the distance betweenthe laser head 200 and the surface being processed. Such a sensor 250can also provide a measure of the amount of material removed from thesurface.

In certain embodiments, the sensor 250 is coupled to the controller 500,and the controller 500 is adapted to transmit control signals to thelaser base unit 300 in response to signals from the sensor 250. Thelaser base unit 300 can be adapted to adjust one or more parameters ofthe laser light in response to the control signals. In this way, thedepth information from the sensor 250 can be used in real-time to adjustthe focus or other parameters of the laser light.

In other embodiments, the controller 500 is adapted to transmit controlsignals to the laser manipulation system 100 in response to signals fromthe sensor 250. The laser manipulation system 100 is adapted to adjustthe relative distance between the laser head 200 and the interactionregion in response to the control signals. In addition, the lasermanipulation system 100 can be adapted to adjust the position of thelaser head 200 along the surface of the structure in response to thecontrol signals. In this way, the depth information from the sensor 250at a first location can be used in real-time to move the laser light toanother location along the surface once a desired depth at the firstlocation is achieved.

In other embodiments, the sensor 250 is used in conjunction withstatistical methods to determine the depth of the interaction region. Insuch embodiments, the sensor 250 is first used in a measurement phase todevelop statistical data which correlates penetration depths withcertain processing parameters (e.g., material being processed, lightintensity). During the measurement phase, selected processing parametersare systematically varied for processing a test or sample surfacesindicative of the surfaces of the structure to be processed. The sensor250 is used in the measurement phase to determine the depth of theinteraction region corresponding to these processing parameters. Incertain such embodiments, the sensor 250 can be separate from the laserhead 200, and can be used during the processing of the structure orduring periods when the processing has been temporarily halted in orderto measure the depth of the interaction region. Exemplary sensors 250compatible with such embodiments include, but are not limited to,calipers or other manual measuring devices which are inserted into theresultant hole to determine the depth of the interaction region.

In certain embodiments, the controller 500 contains this resultingstatistical data regarding the correlation between the processingparameters and the depth of the interaction region. During a subsequentprocessing phase, the structure is processed, but rather than using thesensor 250 at this time, the controller 500 can be adapted to determinethe relative distance by accessing the statistical data corresponding tothe particular processing parameters being used. Such an approachrepresents a reliable and cost-effective approach for determining thedepth of the interaction region while processing the structure.

In alternative embodiments, the sensor 250 is adapted to provide ameasure of the distance between the laser head 200 and the surface ofthe structure. In such embodiments, the sensor 250 can be adapted toprovide a fail condition signal to the controller 500 upon detection ofthe relative distance between the laser head 200 and the structureexceeding a predetermined distance. Such a fail condition may resultfrom the apparatus 50 inadvertently becoming detached from thestructure. The controller 500 can be adapted to respond to the failcondition signal by sending appropriate signals to the laser base unit300 to halt the transmission of energy between the laser base unit 300and the laser head 200. In certain embodiments, the transmission ispreferably halted when the laser head 200 is further than one centimeterfrom the surface of the structure. In this way, the apparatus 50 canutilize the sensor 250 to insure that laser light is not emitted unlessthe containment plenum 240 is in contact with the structure. In certainembodiments, the sensor 250 comprises a proximity switch which contactsthe surface of the structure while the apparatus 50 is attached to thestructure.

Laser Manipulation System

In certain embodiments, the laser manipulation system 100 serves toaccurately and repeatedly position the laser head 200 in relation to thestructure so as to provide articulated robotic motion generally parallelto the surface to be processed. To do so, the laser manipulation system100 can be releasably affixed to the structure to be processed, and canthen accurately move the laser head 200 in proximity to that surface.FIGS. 6A and 6B schematically illustrate two opposite elevatedperspectives of an embodiment in which the laser manipulation system 100comprises an anchoring mechanism 110 adapted to be releasably coupled tothe structure and a positioning mechanism 121 coupled to the anchoringmechanism 110 and coupled to the laser head 200. In certain embodiments,the laser manipulation system 100 can be advantageously disassembled andreassembled for transport, storage, or maintenance.

Anchoring Mechanism

Certain embodiments of the laser manipulation system 100 comprise ananchoring mechanism 110 to releasably affix the laser manipulationsystem 100 to the structure to be processed. The anchoring mechanism 110can be adapted to be releasably coupled to the structure and cancomprise one or more attachment interfaces 111.

In the embodiment schematically illustrated in FIG. 6B, the anchoringmechanism 110 comprises a pair of attachment interfaces 111. Eachattachment interface 111 comprises at least one resilient vacuum pad112, at least one interface mounting device 114, at least one vacuumconduit 116, at least one mounting connector 118, and a coupler 119adapted to couple the attachment interface 111 of the anchoringmechanism 110 to the positioning mechanism 121. While the embodimentschematically illustrated in FIGS. 6A and 6B have two vacuum pads 112for each of the two attachment interfaces 111, other embodiments utilizeany configuration or number of attachment interfaces 111 and vacuum pads112.

In the embodiment illustrated by FIG. 7, two vacuum pads 112 are coupledto the interface mounting device 114. In certain embodiments, eachvacuum pad 112 comprises a circular rubber pad which forms aneffectively air-tight region when placed on the structure. Each vacuumpad 112 is fluidly coupled to at least one vacuum generator (not shown)via a vacuum conduit 116 (e.g., a flexible hose). The vacuum generatormay use fluid power (e.g., compressed air) to generate the vacuum, or itmay use an external vacuum source. The vacuum generator draws air outfrom the air-tight region between the vacuum pad 112 and the structurevia the vacuum conduit 116, thereby creating a vacuum within theair-tight region. Atmospheric pressure provides a force which reversiblyaffixes the vacuum pad 112 to the structure.

The interface mounting device 114 comprises a rigid metal support uponwhich is mounted the vacuum pads 112, the mounting connector 118, andthe coupler 119. In certain embodiments, the mounting connector 118 cancomprise a ground-based support connector 118 a adapted to be releasablyattached to a ground-based support system 700, as described more fullybelow. In other embodiments, the mounting connector 118 can comprise atleast one suspension-based support connector 118 b adapted to bereleasably attached to a suspension-based support system 800, asdescribed more fully below. The coupler 119 is adapted to releasablycouple the interface mounting device 114 to the positioning mechanism121. In certain embodiments, the coupler 119 comprises at least oneprotrusion which is connectable to at least one corresponding recess inthe positioning mechanism 121.

In alternative embodiments, the anchoring mechanism 110 can compriseother technologies for anchoring the apparatus 50 to the structure to beprocessed. These other technologies include, but are not limited to, awinch, suction devices (e.g., cups, gekkomats, or skirts) affixed to theapparatus 50 or on quasi-tank treads, mobile scaffolding suspended fromthe structure, and a rigid ladder. These technologies can also be usedin combination with one another in certain embodiments of the anchoringmechanism 110.

Positioning Mechanism

Certain embodiments of the laser manipulation system 100 comprise apositioning mechanism 121 to accurately move the laser head 200 while inproximity to the structure to be processed. FIG. 8 schematicallyillustrates an exploded view of one embodiment of the positioningmechanism 121 along with the attachment interfaces 111 of the anchoringmechanism 110. The positioning mechanism 121 of FIG. 8 comprises afirst-axis position system 130, a second-axis position system 150, aninterface 140, and a laser head receiver 220. The first-axis positionsystem 130 is releasably coupled to the attachment interfaces 111 of theanchoring mechanism 110 by at least one coupler 132. The interface 140(comprising a first piece 140 a and a second piece 140 b in theembodiment of FIG. 8) releasably couples the second-axis position system150 to the first-axis position system 130. The laser head receiver 220is releasably coupled to the second-axis position system 150, and isadapted to be releasably coupled to the housing 230 of the laser head200.

In certain embodiments, the first-axis position system 130 comprises atleast one coupler 132 having a recess which is releasably connectable toat least one corresponding protrusion of the coupler 119 of theanchoring mechanism 110. Such embodiments are advantageouslydisassembled and reassembled for transport, storage, or maintenance ofthe positioning mechanism 121. Other embodiments can have the first-axisposition system 130 fixedly coupled to the anchoring mechanism 110.

In certain embodiments, the first-axis position system 130 moves thelaser head 200 in a first direction substantially parallel to thesurface of the structure. In the embodiment schematically illustrated byFIG. 9, the first-axis position system 130 further comprises a firstrail 134, a first drive 136, and a first stage 138. The first stage 138is movably coupled to the first rail 134 under the influence of thefirst drive 136. The first piece 140 a of the interface 140 is fixedlycoupled to the first stage 138 so that the first drive 136 can be usedto move the interface 140 along the first rail 134. In certainembodiments, the first-axis position system 130 further comprisessensors, limit switches, or other devices which provide informationregarding the position of the first stage 138 along the first rail 134.This information can be provided to the controller 500, which is adaptedto transmit control signals to the first drive 136 or other componentsof the laser manipulation system 100 in response to this information.

Exemplary first drives 136 include, but are not limited to, hydraulicdrives, pneumatic drives, electromechanical drives, screw drives, andbelt drives. First rails 134, first drives 136, and first stages 138compatible with embodiments described herein are available fromTol-O-Matic, Inc. of Hamel, Minn. Other types and configurations offirst rails 134, first drives 136, and first stages 138 are alsocompatible with embodiments described herein.

In certain embodiments, the second-axis position system 150 moves thelaser head 200 in a second direction substantially parallel to thesurface of the structure. The second direction in certain embodiments issubstantially perpendicular to the first direction of the first-axisposition system 130. In the embodiment schematically illustrated by FIG.10, the second-axis position system 150 comprises a second rail 152, asecond drive 154, and a second stage 156. In certain embodiments, thefirst-axis position system 130 and the second-axis position system 150provide linear movements of the laser head 200. In other embodiments,the first-axis position system 130 and the second-axis position system150 provide circular and axial movements of the laser head 200,respectively.

In certain embodiments, the second stage 156 is movably coupled to thesecond rail 152 under the influence of the second drive 154. The laserhead receiver 220 is releasably coupled to the second stage 156 so thatthe second drive 154 can be used to move the laser head receiver 220along the second rail 152. In certain embodiments, the second-axisposition system 150 further comprises sensors, limit switches, or otherdevices which provide information regarding the position of the secondstage 156 along the second rail 152. This information can be provided tothe controller 500, which is adapted to transmit control signals to thesecond drive 154 or other components of the laser manipulation system100 in response to this information.

Exemplary second drives 154 include, but are not limited to, hydraulicdrives, pneumatic drives, electromechanical drives, screw drives, andbelt drives. Second rails 152, second drives 154, and second stages 156compatible with embodiments described herein are available fromTol-O-Matic, Inc. of Hamel, Minn. Other types and configurations ofsecond rails 152, second drives 154, and second stages 156 are alsocompatible with embodiments described herein.

In certain embodiments, the second rail 152 is fixedly coupled to thesecond piece 140 b of the interface 140. The second piece 140 b cancomprise at least one recess which is releasably connectable to at leastone corresponding protrusion of the first piece 140 a of the interface140. Such embodiments are advantageously disassembled and reassembledfor transport, storage, or maintenance of the positioning mechanism 121.In other embodiments, the interface 140 can be made of a single piecewhich is releasably coupled to one or both of the first stage 138 andthe second rail 152. Other embodiments are not configured for convenientdisassembly (e.g., having an interface 140 made of a single piece andthat is fixedly coupled to both the first stage 138 and the second rail152).

In certain embodiments, the interface 140 comprises a tilt mechanism 144to adjust the relative orientation between the first rail 134 and thesecond rail 152. As schematically illustrated in FIG. 11A, the firstpiece 140 a of the interface 140 is coupled to the first stage 138 onthe first rail 134, and comprises a pair of protuberances 142 adapted tocouple with corresponding recesses of the second piece 140 b of theinterface 140. The tilt mechanism 144 comprises a first plate 145, ahinge 146, a second plate 147, and a pair of support braces 148. Thefirst plate 145 is fixedly mounted to the first stage 138 and issubstantially parallel to the surface upon which the anchoring mechanism110 is mounted. The second plate 147 is pivotally coupled to the firstplate 145 by the hinge 146, and can be locked in place by the supportbraces 148.

In FIG. 11A, the tilt mechanism 144 is configured so that the firstplate 145 and the second plate 147 are substantially parallel to oneanother. In this configuration, the plane of movement defined by thefirst direction and the second direction of the laser head 200 issubstantially parallel to the surface upon which the anchoring mechanism110 is coupled. In FIG. 11B, the tilt mechanism 144 is configured sothat the second plate 147 is at a non-zero angle (e.g., 90 degrees)relative to the first plate 145. In this configuration, the plane ofmovement defined by the first direction and the second direction of thelaser head 200 is at a non-zero angle relative to the surface upon whichthe anchoring mechanism 110 is coupled.

In certain embodiments, the laser head receiver 220 is releasablycoupled the housing 230 of the laser head 200. FIG. 12 schematicallyillustrates a laser head receiver 220 compatible with embodimentsdescribed herein. The laser head receiver 220 is coupled to the secondstage 156 and comprises a releasable clamp 222 and a third-axis positionsystem 224. The clamp 222 is adapted to hold the housing 230 of thelaser head 200. The third-axis position system 224 is adapted to adjustthe relative distance between the laser head 200 and the structure beingprocessed. In certain embodiments, the third-axis position system 224comprises a screw drive which moves the clamp 222 substantiallyperpendicularly to the second rail 152. In certain embodiments, asschematically illustrated by FIG. 12, the screw drive is manuallyactuated by a handle 226, which can be rotated to move the clamp 222. Inother embodiments, the screw drive is automatically controlled byequipment responsive to control signals from the controller 500.

Ground-Based Support System

In certain embodiments, the apparatus 50 can be utilized with aground-based support system 700 which is releasably coupled to theapparatus 50. The interface mounting devices 114 can each comprise aground-based support connector 118 a adapted to releasably couple to theground-based support system 700. The ground-based support system 700advantageously attaches to various types of external boom systems, suchas commercially-available lifting- or positioning-type systems, whichcan support some of the weight of the apparatus 50, thereby reducing theweight load supported by the anchoring mechanism 110. The ground-basedsupport system 700 can be used to facilitate use of the apparatus 50 onsubstantially vertical surfaces (e.g., walls) or on substantiallyhorizontal surfaces (e.g., ceilings).

In certain embodiments, the ground-based support system 700 includes asupport structure 710 such as that schematically illustrated in FIG. 13.The support structure 710 of FIG. 13 comprises a boom connector 712, arotational mount 714, a spreader member 716, a pair of primary posts718, and a pair of auxiliary posts 720. The boom connector 712 isadapted to attach to a selected external boom system. The rotationalmount 714 is adapted to be rotatably coupled to the boom connector 712and fixedly coupled to the spreader member 716 so that the boomconnector 712 can be advantageously rotated relative to the supportstructure 710.

The primary posts 718 are coupled to the spreader member 716 and aresubstantially parallel to one another. Each of the primary posts 718 isadapted to be coupled to one of the ground-based support connectors 118a of the interface mounting devices 114. The primary posts 718 can eachbe coupled to the spreader member 716 at various positions so that theyare aligned with the ground-based support connectors 118 a. Each primarypost 718 is also coupled to, and is substantially perpendicular to, anauxiliary post 720. In such embodiments, rather than having the primaryposts 718 coupled to the ground-based support connectors 118 a, theauxiliary posts 720 can be coupled to the ground-based supportconnectors 118 a, thereby effectively rotating the support structure 710by 90 degrees relative to the anchoring mechanism 110. Such embodimentsadvantageously provide adjustability for processing variousconfigurations of structures and to permit alternative configurationsbest suited for particular applications.

Suspension-Based Support System

Alternatively, the apparatus 50 can be utilized with a suspension-basedsupport system 800 which is releasably coupled to the apparatus 50. Theinterface mounting devices 114 can each comprise at least onesuspension-based support connector 118 b adapted to releasably couple tothe suspension-based support system 800. The suspension-based supportsystem 800 advantageously supports some of the weight of the apparatus50, thereby reducing the weight load supported by the anchoringmechanism 110. The suspension-based support system 800 can be used tofacilitate use of the apparatus 50 on substantially vertical surfaces(e.g., outside walls).

In certain embodiments, as schematically illustrated in FIG. 14A, thesuspension-based support system 800 comprises a winch 810, a primarycable 812, and a pair of secondary cables 814. The winch 810 ispositioned on the roof or other portion of a structure to be processed.The winch 810 is coupled to the primary cable 812, which is coupled tothe secondary cables 814. The secondary cables 814 are each coupled to asuspension-based support connector 118 b of the interface mountingdevice 114 of the anchoring mechanism 110. FIG. 14B schematicallyillustrates one embodiment of the apparatus having the suspension-basedsupport connectors 118 b. The apparatus 50 can then be lowered or raisedby utilizing the winch 810 to shorten or lengthen the working length ofthe primary cable 814. In alternative embodiments, the ground-basedsupport connectors 118 a can be configured to serve also as thesuspension-based support connectors 118 b.

Controller

The controller 500 is electrically coupled to the laser base unit 300and to the laser manipulation system 100, and is adapted to transmitcontrol signals to the laser base unit 300 and to the laser manipulationsystem 100. FIG. 15 schematically illustrates an embodiment of acontroller 500 in accordance with embodiments described herein. Thecontroller 500 comprises a control panel 510, a microprocessor 520, alaser generator interface 530, a positioning system interface 540, asensor interface 550, and a user interface 560.

In certain embodiments, the control panel 510 includes a main powersupply, main power switch, emergency power off switch, and variouselectrical connectors adapted to couple to other components of thecontroller 500. The control panel 510 is adapted to be coupled to anexternal power source (not shown in FIG. 15) and to provide power tovarious components of the apparatus 50.

In certain embodiments, the microprocessor 520 can comprise aProgrammable Logic Controller microprocessor (PLC). PLCs are rugged,reliable, and easy-to-configure, and exemplary PLCs are available fromRockwell Automation of Milwaukee, Wis., Schneider Electric of Palatine,Ill., and Siemens AG of Munich, Germany. In alternative embodiments, themicroprocessor 520 comprises a personal computer microprocessor, orPC/104 embedded PC modules which provide easy and flexibleimplementation. The microprocessor 520 can be adapted to respond toinput signals from the user (via the user interface 560), as well asfrom various sensors of the apparatus 50 (via the sensor interface 550),by transmitting control signals to the other components of the apparatus50 (via the laser generator interface 530 and the positioning systeminterface 540) to achieve the desired cutting or drilling pattern.

The microprocessor 520 can be implemented in hardware, software, or acombination of the two. When implemented in a combination of hardwareand software, the software can reside on a processor-readable storagemedium. In addition, the microprocessor 520 of certain embodimentscomprises memory to hold information used during operation.

In certain embodiments, the laser generator interface 530 is coupled tothe laser base unit 300 and is adapted to transmit control signals fromthe microprocessor 520 to various components of the laser base unit 300.For example, the laser generator interface 530 can transmit controlsignals to the laser generator 310 to set desired operationalparameters, including, but not limited to, laser power output levels andlaser pulse profiles and timing. In addition, the laser generatorinterface 530 can transmit control signals to the cooling subsystem 320to set appropriate cooling levels, the source of compressed gas coupledto the compressed gas inlet 249 of the containment plenum 240, or to thevacuum generator coupled to the extraction port 248.

In certain embodiments, the positioning system interface 540 is coupledto the positioning mechanism 121 of the laser manipulation system 100and is compatible with the first-axis position system 130 andsecond-axis position system 150, as described above. In certain suchembodiments, the positioning system interface 540 comprisesservo-drivers for the first-axis position system 130 and the second-axisposition system 150. The servo-drivers are preferably responsive tocontrol signals from the microprocessor 520 to generate driving voltagesand currents for the first drive 136 and the second drive 154. In thisway, the controller 500 can determine how the laser head 200 is scannedacross the surface of the structure. In certain embodiments, theservo-drivers receive their power from the control panel 510 of thecontroller 500. In embodiments in which the positioning mechanism 121further comprises a third-axis position system, the positioning systeminterface 540 further comprises an appropriate servo-driver so that thecontroller 500 can determine the relative distance between the laserhead 200 and the structure surface being processed.

In certain embodiments, the sensor interface 550 is coupled to varioussensors (not shown in FIG. 15) of the apparatus 50 which provide dataupon which operation parameters can be selected or modified. Forexample, as described above, the laser head 200 can comprise a sensor250 adapted to measure the relative distance between the laser head 200and the interaction region. The sensor interface 550 of such embodimentsreceives data from the sensor 250 and provide this data to themicroprocessor 520. The microprocessor 520 can then adjust variousoperational parameters of the laser base unit 300 and/or the lasermanipulation system 100, as appropriate, in real-time. Other sensorswhich can be coupled to the controller 500 via the sensor interface 550include, but are not limited to, proximity sensors to confirm that thelaser head 200 is in position relative to the surface being processed,temperature or flow sensors for the various cooling, compressed air, andvacuum systems, and rebar detectors (as described more fully below).

In certain embodiments, the user interface 560 adapted to provideinformation regarding the apparatus 50 to the user and to receive userinput which is transmitted to the microprocessor 520. In certainembodiments, the user interface 560 comprises a control pendant 570which is electrically coupled to the microprocessor 520. Asschematically illustrated in FIG. 16, in certain embodiments, thecontrol pendant 570 comprises a screen 572 and a plurality of buttons574.

The screen 572 can be used to display status information and operationalparameter information to the user. Exemplary screens 572 include, butare not limited to, liquid-crystal displays. The buttons 574 can be usedto allow a user to input data which is used by the microprocessor 520 toset operational parameters of the apparatus 50. Other embodiments canuse other technologies for communicating user input to the apparatus 50,including, but not limited to, keyboard, mouse, touchpad, andpotentiometer knobs and/or dials. In certain embodiments, the controlpendant 570 is hard-wired to the apparatus 50, while in otherembodiments, the control pendant 570 communicates remotely (e.g.,wirelessly) with the apparatus 50.

In certain embodiments, the control pendant 570 further comprises anemergency stop button and a cycle stop button. Upon pressing theemergency stop button, the apparatus 50 immediately ceases all movementand the laser irradiation is immediately halted. Upon pressing the cyclestop button, the apparatus 50 similarly ceases all movement and haltslaser irradiation corresponding to the cutting sequence being performed,but the user is then provided with the option to return to the beginningof the cutting sequence or to re-start cutting at the spot where thecutting sequence was stopped. In certain embodiments, the controlpendant 570 further comprises a “dead man switch,” which must bemanually actuated by the user for the apparatus 50 to perform. Such aswitch provides a measure of safety by ensuring that the apparatus 50 isnot run without someone actively using the control pendant 570.

FIGS. 17A-17H illustrate a set of exemplary screen displays of thecontrol pendant 570. The function of each of the buttons 574 along theleft and right sides of the screen 572 is dependent on the operationmode of the apparatus 50. Each of the screen displays providesinformation regarding system status along with relevant informationregarding the current operation mode.

The “MAIN SCREEN” display of FIG. 17A comprises a “Machine Status”field, a “System Status” field, and label fields corresponding to thefunctions of some or all of the buttons 574 of the control pendant 570.The “Machine Status” field includes a text message which describes whatthe apparatus 50 is doing and what the user may do next. The “SystemStatus” field includes a box which shows the operational mode of theapparatus 50. In the example illustrated by FIG. 17A, the apparatus isin “maintenance mode.” The “System Status” field also includes aplurality of status boxes which indicate the status of variouscomponents of the apparatus 50, including, but not limited to, thevacuum pads 112 of the anchoring system 110, the air or vacuum pressure,the first-axis position system 130, and the second-axis position system150. The “System Status” field also indicates whether there are anyfaults sensed with the laser base unit 300. In certain embodiments,nominal status of a component is shown with the corresponding status boxas green. The ready state of the apparatus 50 is illustrated by havingall the system status boxes appear as green. If the status of one ofthese components is outside operational parameters, the correspondingstatus box is shown as red, and the system interlocks are enabled,preventing operation of the apparatus 50. Upon startup, the systeminterlocks are enabled and must be cleared prior to operation of theapparatus 50. The text messages of the “Machine Status” field provideinformation regarding the actions to be performed to place the apparatus50 within operational parameters and to clear the system interlocks.Upon clearing all the system interlocks, the “Machine Status” field willindicate that the apparatus 50 is ready to be used.

The “SELECT OPERATION SCREEN” display of FIG. 17B comprises the “MachineStatus” field, the “System Status” field, and the label fieldscorresponding to the functions of some or all of the buttons 574. The“System Status” field includes information regarding the position of thelaser head 200 along the first-axis position system 130 (referred to asthe long axis) and the second-axis position system 150 (referred to asthe short axis). Some of the buttons 574 are configured to enablevarious operations. For example, four buttons 574 are configured toenable four different operations: circle, pierce, straight cut, andsurface keying, as illustrated in FIG. 17B.

FIG. 17C shows a “CIRCLE SETUP/OPERATION SCREEN” display which providesinformation regarding the circle operation of the apparatus 50 in whichthe laser head 200 moves circularly to cut a circular pattern to adesired depth into the surface of the structure to be processed. Incertain embodiments, the circle operation can be used for “trepanning,”whereby a solid circular core is cut and removed from the surface,leaving a circular hole.

A “Circle Status” field provides information regarding the status of thecircle operation and corresponding instructions to the user. Thestarting position of the laser head 200 along the first-axis positionsystem 130 and the second-axis position system 150 are provided in the“System Status” field. A “Circle Parameters” field provides informationregarding various parameters associated with the cutting of a circularpattern, including, but not limited to, the number of revolutions aroundthe circular pattern, the diameter, time period that the cutting will beperformed, the speed of motion of the laser head 200 around the circle,and the laser base unit (LBU) program number. In certain embodiments,the LBU program number corresponds to operational parameters of thelaser head 200 including, but not limited to, beam focus and intensity.

In certain embodiments, the various parameters can be changed bytouching the parameter on the screen 572, upon which a numerical keypadwill pop up on the screen 572 so that a new value can be entered. Foreach parameter, the “set point” value corresponds to the value currentlyin memory and the last value that was entered. The “status” valuecorresponds to the current value being selected. Upon saving the newparameter value, the “status” and “set point” values are the same.Pressing the button 574 a labeled “Auto/Dry Run” will initiate thecircular movement of the laser head 200 without activating the laserbeam, to ensure the desired motion. Pressing the button 574 b labeled“Cycle Start” will initiate the cutting of the circular pattern,including both the movement of the laser head 200 and the activation ofthe laser beam. Pressing the button 574 c labeled “Cycle Stop” will haltor pause the cutting and movement, with the option to re-start thecutting and movement where it was halted. Pressing the button 574 dlabeled “Machine Reset” will place the apparatus 50 in a neutralcondition. Pressing the button 574 e labeled “Next” upon completion ofthe cutting will return to the “SELECT OPERATION SCREEN.”

FIG. 17D shows a “PIERCE SETUP/OPERATION SCREEN” display which providesinformation regarding the pierce operation of the apparatus 50 in whichthe laser head 200 drills a hole to a desired depth into the surface ofthe structure to be processed. A “Pierce Status” field providesinformation regarding the status of the pierce operation andcorresponding instructions to the user. The starting position of thelaser head 200 along the first-axis position system 130 and thesecond-axis position system 150 are provided in the “System Status”field. A “Pierce Parameters” field provides information regardingvarious parameters associated with the drilling of a hole. The laserparameters can include, but are not limited to, the laser power, thelaser spot size, and the time period for drilling (each of which caninfluence the diameter of the resultant hole which is formed in thestructure), and the LBU program number. The parameters can be changed asdescribed above. The buttons 574 labeled “Auto/Dry Run,” “Cycle Start,”“Cycle Stop,” “Machine Reset,” and “Next” operate as described above.

FIG. 17E shows a “CUT SETUP/OPERATION SCREEN” display which providesinformation regarding the straight cutting operation of the apparatus 50in which the laser head 200 makes a straight cut to a desired depth inthe surface of the structure to be processed. The straight cut ispreferably along one of the axes of the apparatus 50. A “Cut Status”field provides information regarding the status of the cut operation andcorresponding instructions to the user. The starting position of thelaser head 200 along the first-axis position system 130 and thesecond-axis position system 150 are provided in the “System Status”field. A “Cut Parameters” field provides information regarding variousparameters associated with the cutting, including, but not limited to,the speed of motion of the laser head 200, the length of the cut to bemade, and the LBU program number. The parameters can be changed asdescribed above. The buttons 574 f, 574 g labeled “Long Axis” and “ShortAxis” are used to select either the first axis or the second axisrespectively as the axis of motion of the laser head 200. The buttons574 labeled “Auto/Dry Run,” “Cycle Start,” “Cycle Stop,” “MachineReset,” and “Next” operate as described above.

FIG. 17F shows a “SURFACE KEYING SETUP/OPERATION SCREEN” display whichprovides information regarding the surface keying operation of theapparatus 50 in which the laser head 200 cuts an indentation or key intothe surface of the structure to be processed. The surface keyingoperation includes scanning the laser beam across the surface to createan indentation or “key” in the surface with a desired depth and with agenerally rectangular area. In certain embodiments, the surface keyingoperation can be used to perform “scabbling” of the surface, whereby thesurface is roughened by interaction with the laser beam across an area(e.g., rectangular).

A “Surface Keying Status” field provides information regarding thestatus of the surface keying operation and corresponding instructions tothe user. The starting position of the laser head 200 along thefirst-axis position system 130 and the second-axis position system 150are provided in the “System Status” field. A “Surface Keying Parameters”field provides information regarding various parameters associated withthe cutting, including, but not limited to, the speed of motion of thelaser head 200, the length of the key to be made along the first axisand along the second axis, the offset length that the apparatus 50 willincrement between movement along the first axis and the second axis, andthe LBU program number. The parameters can be changed as describedabove. The buttons 574 f, 574 g labeled “Long Axis” and “Short Axis” areused to select either the first axis or the second axis respectively asthe axis of motion of the laser head 200. The buttons 574 labeled“Auto/Dry Run,” “Cycle Start,” “Cycle Stop,” “Machine Reset,” and “Next”operate as described above.

FIG. 17G shows a “FAULT SCREEN” display which provides informationregarding detected operation faults. A fault occurs when a sensor (e.g.,flowmeters, temperature sensors, safety switches, emergencies stops) ofthe monitored systems detects a non-operational condition, and can occurwhile the apparatus 50 is any of the operational modes and while any ofthe screens are being displayed. When a fault occurs, a scrollingmessage indicating the fault is preferably provided at the bottom of thecurrent screen being displayed. In addition, the “Machine Status” fieldwill indicate to the user to clear the faults. The “FAULT SCREEN” can beaccessed from any of the other screens by pressing an appropriate button574. As illustrated in FIG. 17G, in certain embodiments, the “FAULTSCREEN” displays the detected faults in a table with the relevant data,including, but not limited to, the date and the type of fault. Toprepare the apparatus 50 for operation, the detected faults arepreferably cleared by the user. After clearing the detected faults, theuser can press an appropriate button 574 (e.g., “Acknowledge All”) toacknowledge the faults. If the faults are not cleared, the user canpress an appropriate button 574 (e.g., “Machine Reset”) to return to thescreen being displayed when the fault occurred. Pressing the “MachineReset” button 574 again will return the user to the “MAIN SCREEN” fromwhere the apparatus 50 can be reset.

FIG. 17H shows a “MAINTENANCE SCREEN” display which provides informationregarding the apparatus 50. The maintenance mode can be accessed fromthe “MAIN SCREEN” display by pressing an appropriate button 574. In themaintenance mode, the system interlocks are bypassed, therefore the userpreferably practices particular care to avoid damaging the apparatus 50or people or materials in proximity to the apparatus 50. The“MAINTENANCE SCREEN” can display an appropriate warning to the user.

The maintenance mode provides an opportunity for the user to check theoperation of various components of the apparatus 50 independent of thefault status of the apparatus 50. For example, by pressing appropriatebuttons 574 in the maintenance mode, the vacuum system can be turned onand off, the compressed air can be turned on and off via a solenoidvalve, and the first drive 136 and second drive 154 can be turned on andoff. In addition, the default jog speed of the first axis and secondaxis can be changed by pressing the screen 572 to pop up a numericalkeypad display, as described above.

The “System Status” field also includes a plurality of status boxeswhich indicate the status of various components of the apparatus 50,including, but not limited to, the vacuum pads 112 of the anchoringsystem 110, the air or vacuum pressure, the first-axis position system130, and the second-axis position system 150. The “System Status” fieldalso indicates whether there are any faults sensed with the laser baseunit 300. In certain embodiments, nominal status of a component is shownwith the corresponding status box as green. The ready state of theapparatus 50 is illustrated by having all the system status boxes appearas green. If the status of one of these components is outsideoperational parameters, the corresponding status box is shown as red.

The “MAINTENANCE SCREEN” can also provide the capability to move thelaser head 200 along the first axis and second axis, as desired. A setof three buttons 574 are configured to move the laser head 200 along thefirst axis to a home position, in a forward direction, or in a backwarddirection, respectively. Similarly, another set of three buttons 574 areconfigured for similar movement of the laser head 200 along the secondaxis. The label field for these sets of buttons can include informationregarding the position of the laser head 200 along these two axes.

Detector

In certain embodiments, the controller 500 is coupled to a detector 600adapted to detect embedded material in the structure while processingthe structure, and to transmit detection signals to the controller 500.In certain embodiments, the controller 500 is adapted to avoidsubstantially damaging the embedded material by transmitting appropriatecontrol signals to the laser base unit 300 and the laser manipulationsystem 100. In certain embodiments, the detector 600 is adapted toutilize light emitted by the interaction region during processing todetect embedded material.

Various technologies for detecting embedded material are compatible withembodiments of the present invention. Spectral analysis of the lightemitted by the interaction region during processing can provideinformation regarding the chemical constituents of the material in theinteraction region. By analyzing the wavelength and intensity of thelight, it is possible to determine the composition of the material beingheated and its temperature. Using spectroscopic information, thedetection of embedded materials in certain embodiments relies onmonitoring changes in the light spectrum during processing. With thedifferences in composition of embedded materials, by way of example andnot limitation, such as rebar (e.g., steel) embedded in concrete,variations in the melting and boiling temperatures for the diversematerials will produce noticeable changes in the amount of light, and/orthe wavelength of the light when the laser light impinges and heats theembedded material.

FIG. 18 schematically illustrates a detector 600 compatible withembodiments described herein. The detector 600 comprises a focusing lens610, an optical fiber 620, and a spectrometer 630. The spectrometer 630of certain embodiments comprises an optical grating 632 and a lightsensor 634. In certain embodiments, the spectrometer 630 also comprisesa microprocessor to analyze the resulting spectroscopic data. In otherembodiments, the spectrometer 630 is coupled to such a microprocessor.The focusing lens 610 is positioned to receive light emitted from theinteraction region, which is directed onto the optical fiber 620. Theoptical fiber 620 then delivers the light to the spectrometer 630, andthe optical grating 632 of the spectrometer 630 separates the light intoa spectrum of wavelengths. The separated light having a selected rangeof wavelengths can then be directed onto the light sensor 634 whichgenerates a signal corresponding to the intensity of the light in therange of wavelengths. The spectrometer 630 can monitor specificwavelengths that are associated with various embedded materials in thestructure. In certain embodiments, the spectrometer 630 can monitor therelative intensity of the light at, or in spectral regions in proximityto, these wavelengths. Additionally, at least one neutral density filtermay be employed to decrease the light reaching the spectrometer 630 toimprove spectral analysis performance.

In certain embodiments, at least a portion of the detector 600 ismounted onto the laser head 200. In embodiments in which the focusinglens 610 is part of the laser head 200, the focusing lens 610 can bepositioned close to the axis of the emitted laser light so as to receivelight from the interaction region. In such embodiments, the focusinglens 610 can be behind the nozzle 244 and protected by the compressedair from the compressed air inlet 249, as is the window 243. In certainembodiments, the focusing lens 610 is coaxial with the laser beam, whilein other embodiments, the focusing lens 610 is located off-axis.

Exemplary focusing lenses 610 include, but are not limited to, UV-74from Ocean Optics of Dunedin, Fla. Exemplary optical fibers 620 include,but are not limited to, P400-2-UV/VIS from Ocean Optics of Dunedin, Fla.Exemplary spectrometers 630 include, but are not limited to, USB2000(VIS/UV) from Ocean Optics of Dunedin, Fla.

In certain embodiments, the spectrometer 630 monitors the intensity at aspecific wavelength and the intensities on both sides of thiswavelength. The spectrometer 630 of certain embodiments also monitorsthe reduction of the intensities resulting from the increased depth ofthe hole being drilled. FIG. 19 shows an exemplary graph of the lightspectrum detected upon irradiating concrete with laser light and thelight spectrum detected upon irradiating an embedded rebar. The spectrumfrom concrete shows an emission peak at a wavelength of approximately592 nanometers. The spectrum from rebar does not have this emissionpeak, but instead shows an absorption dip at approximately the samewavelength. Thus, the emission spectrum at about 592 nanometers can beused to provide a real-time indication of whether an embedded rebar isbeing cut by the laser light. For example, by sampling the emissionspectrum at about 588.5 nanometers, 592 nanometers, and 593 nanometers,and calculating the ratio: (2×I₅₉₂)/(I₅₉₃+I_(588.5)), the detector 600can determine whether the emission spectrum has a dip corresponding toconcrete or a peak corresponding to embedded rebar. Other spectroscopicdata can be used in other embodiments.

An alternative technology for detecting embedded materials uses highspeed shutter monitoring. This approach utilizes advances in CoupledCapacitance Discharge (CCD) camera systems to monitor discrete changesin the interactions between the material to be processed and the laserlight. Newer CCD cameras have systems that can decrease the time theshutter is open to about 0.0001 second. At this speed, it is possible tosee many features of the interaction between the laser light and thematerial being processed. Additionally, neutral density filters may beemployed to decrease the glare observed from the incandescentinteraction of the laser light and the material to be processed and tobetter image the interaction region.

Numerous alterations, modifications, and variations of the variousembodiments disclosed herein will be apparent to those skilled in theart and they are all anticipated and contemplated to be within thespirit and scope of the instant invention. For example, althoughspecific embodiments have been described in detail, those with skill inthe art will understand that the preceding embodiments and variationscan be modified to incorporate various types of substitute and/oradditional or alternative materials, relative arrangement of elements,and dimensional configurations. Accordingly, even though only fewvariations of the present invention are described herein, it is to beunderstood that the practice of such additional modifications andvariations and the equivalents thereof, are within the spirit and scopeof the invention as defined in the following claims.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or acts for performing the functions incombination with other claimed elements as specifically claimed.

1. A system for detecting laser-irradiated embedded material in astructure, the system comprising: an optical system receiving lightemitted from an interaction region of the structure in response toirradiation of the interaction region with laser light that heatsmaterial in the interaction region; a spectral analyzer responsive to atleast a portion of the received light by generating a detection signalindicative of the embedded material within the interaction region; and acontroller configured to adjust the laser light irradiating theinteraction region in response to the detection signal.
 2. The system ofclaim 1, wherein the optical system comprises a lens receiving lightemitted from the interaction region and an optical fiber opticallycoupled to the lens and to the spectral analyzer.
 3. The system of claim2, wherein the lens is coaxial with the laser light.
 4. The system ofclaim 2, wherein the lens is off-axis with the laser light.
 5. Thesystem of claim 1, wherein the spectral analyzer comprises: an opticalgrating receiving light from the optical system and to separate thelight into a spectrum of wavelengths; and a light sensor receiving lightin at least a portion of the spectrum and to generate a signalcorresponding to an intensity of the received light.
 6. The system ofclaim 1, wherein the spectral analyzer comprises a coupled-capacitancedischarge (CCD) camera.
 7. The system of claim 1, wherein the spectralanalyzer comprises at least one neutral density filter.
 8. The system ofclaim 1, wherein the structure comprises concrete and the embeddedmaterial comprises rebar.
 9. A detection system for use duringirradiation of an interaction region of a structure with laser light,the structure comprising embedded material, the detection systemcomprising: means for receiving light emitted from the interactionregion in response to heating of material in the interaction region bylaser irradiation; means for separating the received light into aspectrum of wavelengths; means for analyzing at least a portion of thespectrum for indications of embedded material within the interactionregion; and means for adjusting the laser light irradiating theinteraction region in response to a signal from said analyzing means.10. The detection system of claim 9, wherein the receiving meanscomprises a lens and an optical fiber.
 11. The detection system of claim9, wherein the separating means comprises an optical grating and a lightsensor.
 12. The detection system of claim 9, wherein the analyzing meanscomprises a microprocessor operatively coupled to the separating means.13. The detection system of claim 9, wherein the adjusting meanscomprises a controller operatively coupled to the analyzing means.
 14. Amethod of detecting rebar in an interaction region of a structure withrebar embedded therein, the interaction region irradiated by laserlight, the method comprising: receiving light emitted from theinteraction region in response to laser heating of material in theinteraction region; separating the light into a spectrum of wavelengths;analyzing at least a portion of the spectrum for indications of rebarwithin the interaction region; and adjusting the laser light irradiatingthe interaction region in response to the irradiation.
 15. The method ofclaim 14, wherein the light is received from the interaction regionwhile the interaction region is irradiated with laser light.
 16. Themethod of claim 14, wherein analyzing the at least a portion of thespectrum comprises monitoring the intensity of light having wavelengthsassociated with the embedded rebar.
 17. The method of claim 14, whereinanalyzing the at least a portion of the spectrum comprises monitoringdiscrete changes in interactions between the laser light and material inthe interaction region.